Brain-derived neurotrophic factor levels are higher in those who are physically active and lower in people with cognitive dysfunction. This study investigated whether brain-derived neurotrophic factor mediated or modified the association of sedentary time to MRI-estimated brain volumes in midlife.
Baseline (
Cross-sectionally, baseline participants with the highest sedentary time had a lower total brain (−12.2 cc; 95%CI: −20.7, −3.7), gray matter (−7.8 cc; 95%CI: −14.3, −1.3), and hippocampal volume (−0.2 cc; 95%CI: −0.3, 0.0) compared with populations with the lowest sedentary time. The brain-derived neurotrophic factor levels did not mediate the associations between brain measures and sedentary time. Brain-derived neurotrophic factor was found to moderate associations of sedentary time to total brain and white matter volume such that the brain volume difference between high and low sedentary time decreased as brain-derived neurotrophic factor levels increased. Longitudinally, higher baseline brain-derived neurotrophic factor level was associated with less brain volume decline. The longitudinal associations did not differ by sedentary time, and brain-derived neurotrophic factor did not mediate or moderate the association of sedentary time to brain measure changes.
Higher brain-derived neurotrophic factor levels may buffer the negative effects of sedentary time on the brain.